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Hydrolysis mechanism of YbB_(2)C_(2)and the microstructure of the carbon derived from the hydrolysis reaction

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Journal of Materials Science & Technology 2024年第4期171卷 209-221页

作者： Zhihui Li Hao Zhang jixin chen Jiemin Wang Xiaohui Wang Jinxing Yang Chao Zhang Zerong Zhang Hongyang Liu Fei Huang Meishuan Li Fei Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shanghai Key Laboratory for High Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Carbide-derived carbon(CDC)materials have gained great attention due to the excellent properties for various potential ***,graphite crystal is formed during a room-temperature hydrolysis pro-cess of layered compound YbB_(2)C_(2).The formation mechanism can be demonstrated by a YbB_(2)C_(2)molecular cell:Yb^(3+)acts as a cathode where H_(2)O molecule is reduced to H atom and OH^(−)ion,while(B_(2)C_(2))^(3−)acts as an anode where OH−ion is oxidized to O ***,YbB_(2)C_(2)molecular cell begins to disintegrate,i.e.,Yb^(3+)ion,B and C atoms dissociate from the molecular *** as-produced C atoms combine to form graphite *** initial graphite crystal is a cabbage-like microsphere,and then it gradually disintegrates and transforms into layered *** addition,YbB_(6),Yb_(3)(OH)_(3)n(BO_(3))_((3-n))sol,hydrogen,hydrocarbons,and carbon oxides form *** method provides a general and inexpensive route to obtain carbide-derived graphite crystal.

关键词： Carbide-derived carbon YbB_(2)C_(2) Hydrolysis Molecular cell First-principles calculations

An Ultra-wideband Doubler Chain with 43–65 dBc Fundamental Rejection in Ku/K/Ka Band

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Chinese Journal of Electronics 2024年第5期33卷 1204-1217页

作者： Long WANG jixin chen Debin HOU Xiaojie XU Zekun LI Dawei TANG Rui ZHOU Hao QI Yu XIANG State Key Laboratory of Millimeter Waves Southeast University MISIC Microelectronics Co.Ltd.

In this paper, a double-balanced doubler chain with >43-dBc fundamental rejection over an ultra-wide bandwidth in 0.13-μm SiGe BiCMOS technology is proposed. To achieve high fundamental rejection, high output power, and high conversion gain over an ultra-wideband, a double-balanced doubler chain with pre-and post-drivers employs a bandwidth broadening technique and a ground shielding strategy. Analysis and comparison of the singlebalanced and double-balanced doublers were conducted, with a focus on their fundamental rejection and circuit imbalance. Three doublers, including a passive single-balanced doubler, an active single-balanced doubler, and a passive double-balanced doubler were designed to verify the performance and characteristics of the single-and doublebalanced doublers. Measurements show that the proposed double-balanced doubler chain has approximately 15 dB better fundamental rejection, and more than twice the relative bandwidth compared to the single-balanced doubler chain fabricated with the same process. Over an 86.9% 3-dB bandwidth from 13.4 GHz to 34 GHz, the double-balanced doubler chain delivers 14.7-dBm peak output power and has >43-/33-dBc fundamental/third-harmonic rejection. To the authors' best knowledge, the proposed double-balanced doubler chain shows the highest fundamental rejection over an ultra-wideband among silicon-based doublers at millimeter-wave frequency bands.

关键词： Millimeter wave technology Bandwidth Harmonic analysis Frequency conversion Millimeter wave communication Power generation Gain Doubler Double-balanced Fundamental rejection Single-balanced FREQUENCY DOUBLER POWER-AMPLIFIER GAIN COMPENSATION EFFICIENCY SILICON

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基于Voronoi图的无线传感网络覆盖盲区检测方法

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传感技术学报 2024年第1期37卷 136-141页

作者：陈振峰陈纪鑫广州番禺职业技术学院财经学院广东广州511483 华南理工大学建筑学院广东广州510614

传感网络的空洞暴露程度较少,在检测网络覆盖情况时更容易出现误差,影响盲区的检测效果。为此,提出基于Voronoi图的无线传感网络覆盖盲区检测方法。根据节点分布关系推测无线传感网络覆盖情况,在Voronoi图的指导下排除已覆盖区域,获取... 详细信息

传感网络的空洞暴露程度较少,在检测网络覆盖情况时更容易出现误差,影响盲区的检测效果。为此,提出基于Voronoi图的无线传感网络覆盖盲区检测方法。根据节点分布关系推测无线传感网络覆盖情况,在Voronoi图的指导下排除已覆盖区域,获取具备检测条件的未覆盖无线传感网络空洞。计算网络空洞的暴露程度和节点能量,作为特征样本输入粒子群分离器中,根据分类器的输出结果,实现无线传感网络覆盖盲区检测。仿真结果表明,所提方法不同覆盖盲区数量下的检测时长低于0.2 s、不同节点数量下的检测能耗低于20 J、不同空洞圆心距下的覆盖盲区差异度最高为0.24,证明所提方法具有较好的无线传感网络覆盖盲区检测效果。

关键词：无线传感网络覆盖盲区盲区检测网络空洞 Voronoi图

前交叉韧带重建后本体感觉训练:提高关节稳定性及运动平衡能力

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中国组织工程研究 2024年第27期28卷 4421-4428页

作者：叶云天陈继鑫刘爱峰天津中医药大学第一附属医院骨伤科天津市300381 国家中医针灸临床医学研究中心天津市300381

背景:前交叉韧带断裂是严重影响生活及运动表现的损伤之一,作为稳定结构,前交叉韧带对维持运动表现有着无法替代的作用。鉴于其严重的损伤表现,目前临床治疗行前交叉韧带重建手术。由于前交叉韧带损伤会引起机械感受器损失,进而引起本... 详细信息

背景:前交叉韧带断裂是严重影响生活及运动表现的损伤之一,作为稳定结构,前交叉韧带对维持运动表现有着无法替代的作用。鉴于其严重的损伤表现,目前临床治疗行前交叉韧带重建手术。由于前交叉韧带损伤会引起机械感受器损失,进而引起本体感觉降低,为患者运动表现恢复带来极大困扰。目的:总结本体感觉训练对前交叉韧带重建术后临床效果的影响,探讨其背后机制,以期为临床防治提供更多参考。方法:计算机检索PubMed、中国知网、万方数据、维普数据库2013年1月至2023年3月收录的与前交叉韧带重建后本体感觉训练提高关节稳定性及运动平衡能力相关的应用文献,按纳入、排除标准筛选后最终纳入108篇文献进行综述。结果与结论:①本体感觉训练可有效改善前交叉韧带重建术后患者位置觉、运动觉等本体感觉功能,提高了关节稳定性、姿势控制及运动能力;②本体感觉训练通过刺激膝关节周围本体感受器、激活脊髓反射刺激、大脑运动控制强化和认知处理,提升三方面机制,改善本体感觉功能;③本体感觉训练可能通过激活生长相关蛋白43活性、Piezo2机械传导器和NT-3/TrkC信号通路等潜在机制,改善本体感觉功能;④前期以水疗法为主,中后期优先考虑神经肌肉训练、单独力量训练及视觉反馈训练;⑤尚未细分重建移植物、性别,以及缺少以联合多种感觉刺激为思路的设备或本体感觉训练方法。

关键词：前交叉韧带前交叉韧带重建本体感觉本体感觉训练应用策略综述

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Ka波段连续波9 W GaN功率放大器

微波学报 2024年第3期40卷 90-92,98页

作者：徐小杰侯德彬陈喆陈继新南京迈矽科微电子科技有限公司南京211100 东南大学毫米波国家重点实验室南京210096

本文研制了一款采用0.15μm碳化硅基氮化镓功率MMIC工艺的Ka波段连续波功率放大器芯片。功率放大器采用了3级共源级联结构。输出级采用了16个晶体管进行功率合成,有效地分散了热分布,输出匹配网络采用低损耗拓扑架构,保证了输出功率与... 详细信息

本文研制了一款采用0.15μm碳化硅基氮化镓功率MMIC工艺的Ka波段连续波功率放大器芯片。功率放大器采用了3级共源级联结构。输出级采用了16个晶体管进行功率合成,有效地分散了热分布,输出匹配网络采用低损耗拓扑架构,保证了输出功率与附加效率。级间匹配采用了最大增益匹配,同时兼顾了小信号增益平坦度。在28 GHz~30 GHz内,小信号增益为25 dB,28 V偏置电压下连续波输出功率大于39 dBm,功率增益为17 dB,附加效率大于25%,热阻为1.41℃/W。输出功率为35 dBm时,IMD 3小于-25 dBc,芯片面积为3.0 mm×3.1 mm。

关键词：氮化镓 Ka波段功率放大器

In-situ Synthesis of Ti_3AlC2/TiC-Al_2O_3 Composite from TiO_2-Al-C System

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Journal of Materials Science & Technology 2006年第4期22卷 455-458页

作者： jixin chen Jialin LI Yanchun ZHOU Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Ti3AlC2/TiC-Al2O3 composite was synthesized by a combustion reaction in TiO2-Al-C system. The effect of the compositions in raw materials on the products was investigated. Ti3AlC2/TiC-Al2O3 composite was obtained at the molar ratio of TiO2：Al：C=3.0：5.0～5.1：1.8～2.0. The reaction path for the 3TiO2-5Al- 2C system was proposed. Al3Ti, Ti203, TiO, and 6-Al2O3 are found to be transitional phases. Finally, Ti3AlC2/TiC-Al2O3 composite forms at～900℃ of furnace temperature. The measured Vickers hardness, fracture toughness, and flexural strength of the nearly dense sample from 3TiO2-5Al-2C are 13.3±1.1 GPa, 5.8±0.3 MPa.m^1/2, and 466±39 MPa, respectively.

关键词： Ti3AlC2 TiC Al2O3 TiO2-Al-C Reaction path

Electrodeposition and Characterization of Ni/Ti_3Si(Al)C_2 Composite Coatings

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Journal of Materials Science & Technology 2011年第11期27卷 1016-1024页

作者： Ying Liang Mingyue Liu jixin chen Xiaoxia Liu Yanchun Zhou Department of Chemistry Northeastern University Shenyang 110819 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Pure nickel and Ni/Ti3Si（AI）C2 composite coatings were prepared by electrodeposition method from an additive-free nickel Watt＇s bath and were characterized by X-ray diffraction, laser confocal microscopy and scanning electron microscopy. The effect of current and Ti3Si（AI）C2 concentration in the solution on the composition, grain size, preferred orientation and surface morphology of the electrodeposited coatings were investigated. （200）-oriented Ni coatings could be deposited at high current （62.5 mA）, while （220）-oriented Ni coatings could be obtained at low current （25 mA）. However, the presence of Ti3Si（Al）C2 particles disturbed the surface texture of Ni crystallites in the composite coatings. Based on the simulated morphology and the observed microstructure, the mechanisms for the change of preferred orientation and crystallite shapes in the presence of Ti3Si（Al）C2 particles were discussed. Moreover, microhardness and friction properties of pure nickel and Ni/Ti3Si（Al）C2 composite coatings were also compared.

关键词： Ni/TiaSi(Al)C2 composite coatings Electrodeposition Preferred orientation Microstructure Mechanical properties

Microstructure and mechanical properties of h-BN/Yb_4Si_2O_7N_2 composites

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Journal of Advanced Ceramics 2018年第4期7卷 317-324页

作者： Juanjuan chen jixin chen Hao ZHANG Minmin HU Meishuan LI Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences University of Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

A series of h-BN based composites with Yb_4Si_2O_7N_2 as a secondary phase were successfully synthesized by an in situ reaction hot pressing method. It was found that the relative density and room-temperature mechanical properties monotonically increased with increasing the content of Yb_4Si_2O_7N_2 from 20 to 50 vol%. When 50 vol% Yb_4Si_2O_7N_2 was introduced, the relative density of the composite reached 98.75%, and its flexural strength, compressive strength, fracture toughness, and hardness reached 338±10 MPa, 803±49 MPa, 2.06±0.06 MPa·m1/2, and 2.69±0.10 GPa, respectively. The strengthening effect of Yb_4Si_2O_7N_2 was mainly attributed to its high modulus and high hardness. Fine microstructure was also advantageous to strength and could lead to more tortuous crack propagation paths and then improve the fracture toughness of the composites simultaneously. Meanwhile, the composites maintained good machinability.

关键词： h-BN/Yb_4Si_2O_7N_2 composites microstructure mechanical properties machinability

Stabilization of mixed-halide lead perovskites under light by photothermal effects

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Journal of Energy Chemistry 2021年第12期30卷 8-11,I0001页

作者： Juvinch R.Vicente Martin E.Kordesch jixin chen Department of Chemistry and Biochemistry Ohio UniversityAthensOH 45701United States Nanoscale and Quantum Phenomena Institute Ohio UniversityAthensOH 45701United States Department of Chemistry University of the Philippines VisayasMiagaoIloilo 5023Philippines Department of Physics and Astronomy Ohio UniversityAthensOH 45701United States

Mixed-halide lead perovskites(MHLPs) are semiconductor materials with bandgaps that are tunable across the visible spectrum and have seen promising applications in photovoltaics and ***, their segregation into phases with enriched halide components, under resonant light illumination and/or electric field, have hindered their practical applications. Herein, we demonstrate the stabilization of the MHLP photoluminescence(PL) peak as a function of their excitation *** effect is associated with the phase segregation of MHLPs and their subsequent remixing by photothermal heating. We conclude that the balance between these opposing processes dictates the equilibrium PL peak of the MHLPs. The findings in this work could serve as a potential approach to obtain MHLP with stable emission peaks under operating conditions.

关键词： Perovskites Phase segregation Photothermal Solar cells LEDs